Neil Heslin, the father of a 6-year-old boy who was slain in the Sandy Hook massacre in Newtown, Conn., on Dec. 14, holds a picture of himself with his son Jesse and wipes his eye while testifying Wednesday on Capitol Hill in Washington before the Senate Judiciary Committee on the Assault Weapons Ban of 2013. (ASSOCIATED PRESS / Susan Walsh)

WASHINGTON (AP) — After weeks of arguing constitutional fine points and citing rival statistics, senators wrangling over gun control saw and heard the anguish of a bereft father.

Neil Heslin, whose 6-year-old son, Jesse, was among those cut down at a Connecticut elementary school in December, asked the Senate Judiciary Committee on Wednesday to ban assault weapons like the one that killed his child.

“I’m not here for the sympathy or the pat on the back,” Heslin, a 50-year-old construction worker, told the senators, weeping openly during much of his hushed 11-minute testimony. “I’m here to speak up for my son.”

At his side were photos: of his son as a baby, of them both taken on Father’s Day, six months before Jesse was among 20 first-graders and six administrators killed at Sandy Hook Elementary School in Newtown, Conn. That massacre has hoisted gun control to a primary political issue this year, though the outcome remains uncertain.

The hearing’s focus was legislation by Sen. Dianne Feinstein, D-Calif., to ban assault weapons and ammunition magazines carrying more than 10 rounds. A Bushmaster assault weapon was used at Newtown by the attacker, Adam Lanza, whose body was found with 30-round magazines.

Feinstein said such a firearm “tears peoples’ bodies apart. I don’t know why as a matter of public policy we can’t say they don’t belong.”’

Republicans had several answers. They argued her proposal would violate the Second Amendment’s right to bear arms and take firearms from law-abiding citizens, and said current laws aimed at keeping guns from criminals are not fully enforced.

“The best way to prevent crazy people” from getting firearms is to better enforce the existing federal background check system, said Sen. Lindsey Graham, R-S.C.

That system is designed to prevent criminals, people with mental problems and others from obtaining guns. It only applies to weapons sold by federally licensed dealers, and expanding that system to nearly all gun transactions is the central proposal in President Barack Obama’s package of gun restrictions he unveiled last month, along with bans on assault weapons and large-capacity magazines.

As if to underscore the hurdles Obama’s plan faces on Capitol Hill, House Judiciary Committee Chairman Bob Goodlatte, R-Va., told reporters Wednesday that he opposed universal background checks like the president wants and predicted it would not be part of his chamber’s gun legislation. He wants the current federal background check system strengthened, improving how states provide it with mental health information about citizens and cracking down on illegal gun trafficking.

At the same time, election results from Tuesday highlighted gun control’s potency as a political issue. Illinois state Rep. Robin Kelly won a House Democratic primary in the state after a political committee favoring firearms curbs financed by New York City Mayor Michael Bloomberg, Independence USA, spent more than $2 million on ads for her. Kelly’s opponent had opposed an assault weapons ban.

The Senate Judiciary panel could begin writing gun legislation Thursday, but that seems all but certain to slip to next week.

At the Senate hearing, spectators dabbed tears from their cheeks as Heslin described his last morning with his son, including getting a final hug as he dropped him off at school. The hearing room was packed with relatives and neighbors of victims of Newtown, as well as people affected by other shootings at Aurora, Colo., and Virginia Tech.

“It’s all going to be OK,” Heslin says his son told him. “And it wasn’t OK.”

Dr. William Begg, an emergency room doctor who treated some Newtown casualties, described assault weapons wounds. Begg noted that the coroner’s report said each child had three to 11 bullet wounds.

“They had such horrific injuries to their little bodies,” said Begg. He said an assault weapons bullet “opens up” and does not travel in a straight line, adding, “That’s not a survivable injury.”

The hearing featured heated exchanges, such as when Graham pressed Milwaukee Police Chief Edward Flynn about the government’s prosecution of only a handful of the roughly 80,000 people annually who fail background checks after falsely stating they qualify for guns.

Former Rep. Sandy Adams, R-Fla., once a law enforcement officer, told the senators they have an opportunity to take effective action against gun violence. She has favored expanding the availability of mental health information to the authorities and opposes taking guns from people.

“It is not time for feel-good legislation so you can say you did something,” she said.

That drew an angry objection from Sen. Richard Durbin, D-Ill., who said, “This is not feel-good legislation.”

Feinstein’s bill — and most of Obama’s guns agenda — will have to overcome opposition from the National Rifle Association, which has long kept lawmakers from enacting gun restrictions.

Another hurdle is uncertain support from moderate Democrats.

Feinstein’s measure has 21 co-sponsors, all Democrats. Including herself, it is sponsored by eight of the 10 Judiciary panel Democrats — precarious for a committee where Democrats outnumber Republicans 10-8. Among those who haven’t co-sponsored the measure is Chairman Patrick Leahy, D-Vt., who did not attend Wednesday’s session.

Her bill would ban future sales of assault weapons and magazines carrying more than 10 rounds of ammunition, exempting those that already exist. It specifically bans 157 firearms but excludes 2,258 others in an effort to avoid barring hunting and sporting weapons.

Meanwhile, the House Education and Workforce Committee debated ways to keep students safe, such as the NRA proposal for more armed guards at schools.

“Two thousand kids die each year in automobiles each year,” said Rep. Phil Roe, R-Tenn., comparing that number with the comparatively few children who die in schools. “Schools are safe places and for the most part they really are.”

Rep. George Miller, D-Calif., said school safety is linked to firearms, saying, “Turning schools into armed fortresses is not the answer.”